My long-term career goal is to lead a productive academic research group, promoting science by conducting impactful cancer biology research and mentoring the next generation of dedicated scientists. I am particularly interested in the mechanisms of cancer development and resistance to therapy in Ras-driven tumors. Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers, and it is almost universally driven by activation of oncogenic Ras. Unfortunately, PDAC mortality rates have remained almost equal to incidence rates over the past few decades. My main objective is to identify novel therapeutic targets in PDAC cells to guide the development of new efficacious drugs and treatment approaches in PDAC patients. A major goal of this K99/R00 proposal is to elucidate a novel signaling module implicated in PDAC: in this module, the SMYD3 lysine methyltransferase activates the MAP3K2 kinase, which in turn activates the MEK5 kinase, leading to activation of the downstream ERK5 kinase. A second important goal is to uncover molecular mechanisms promoting resistance to drugs targeting the Ras pathway. First, I will focus on defining the role of ERK5 in the initiation and progression of PDAC. The MEK5-ERK5 pathway has been implicated in cell survival and cell motility but its role in PDAC has never been investigated. Aim 1 will test the hypothesis that activation of the SMYD3-ERK5 signaling module, which I have recently observed in PDAC, facilitates early cancer progression by promoting pancreatic cell plasticity, proliferation, and impairing apoptosis in response to oncogenic Ras. I will use genetic and pharmacological approaches to test this hypothesis in mouse models of PDAC, patient derived tumor xenografts, and cancer cell lines. Clinical trials with inhibitors of kinases in the canonical Ras pathway have had disappointing results, in part because of the rapid emergence of resistant tumors. I have generated pre-clinical models to study tumors resistant to Ras pathway inhibitors and found amplification of SMYD3-ERK5 activity during tumor relapse. Aim 2 will utilize genetic and pharmacological approaches to characterize the functional role of the SMYD3- ERK5 signaling module in resistant tumors in vivo and in vitro. Finally, in Aim 3, I will perform an unbiased screen of transcriptional targets and interacting protein partners of ERK5 to elucidate its mechanisms of action in PDAC cells and identify novel key regulators of PDAC development and resistance to Ras pathway inhibitors. Candidate targets, including preliminarily identified YAP1 transcription factor, will be tested in a novel mouse model of human PDAC that I have developed for rapid investigation of putative regulators of disease development in vivo. A K99/R00 training award will allow me to carry out this transformative project, further developing my current skills in mouse genetics and cancer biology, while also allowing me to acquire knowledge in clinical aspects of pancreatic cancer and new expertise in biochemical signaling and systems biology.